high idle on 1990 Chevrolet S10 Blazer

i have a 4.3 liter,high idle when it first starts then after it calms down it idles rough just wonder what options could cause this

Asked by for the 1990 Chevrolet S10 Blazer
Idle control valve, vacuum leak, air intake leak, Manifold Absolute Pressure (MAP) sensor...

Those are places I would begin looking...
ok thanks it gives me a starting point